The advent of micro-power wireless systems has gained increasing importance for a variety of applications. One example of a micro-power system includes sensor applications. For instance, with recent advances in micro-technology and its associated interfaces, signal processing, and RF circuitry, system focus has shifted away from limited macro-sensors communicating with base stations to creating wireless networks of communicating micro-sensors that aggregate complex data to provide rich, multi-dimensional data exchanges. While individual micro-sensor nodes of a given network may not be as accurate as their macro-sensor counterparts, the networking of a large number of nodes enables high quality sensing networks with the additional advantages of deployment and fault-tolerance.
Each node of a micro-power wireless system utilizes a radio (e.g., transmitter and/or receiver) to communicate with the available network. Each radio of the system typically utilizes a reference clock generated from a high quality factor (Q) oscillator. One limitation of high Q-factor oscillators is that they can take significant time to startup upon receiving power which is often on the order of hundreds of microseconds. Low power wireless networks save power by operating in a duty cycled mode where a given device spends most of its time in sleep mode. A given radio typically turns on to send data for only a few hundred microseconds to conserve power. Thus, startup time due to a high-Q oscillator can be longer than the respective data packet itself. Long crystal oscillator startup time therefore can greatly increase power consumption in micro-power networks.